Pressure-gage



I (No Model.)

0. B. BOSWORTH.

PRESSURE GAGE.

No. 393,610. Patented Nov. 27, 1888...

. Ina/e 2 0750 2* Witnessem a raw (f UNITE STATES PATENT OFFICE.

CHARLES B. BOSWORTH, OF EVERETT, ASSIGNOR TO THE CROSBY STEAM GAGE ANDVALVE COMPANY, OFBOSTON, MASSACHUSETTS.

PRESSURE-GAGE.

SBPEC'IPICATION forming part of Letters Patent No. 393,610, datedNovember 27, 1888.

Application filed July 31, 1888. Serial No. 281,536. (No model.)

To aZZ whom, it may concern.-

Be it known that I, CHARLES B. BOSWORTH,

a citizen of the United States, residing at- Everett, in the county ofMiddlesex and State of Massachusetts, have invented certain new anduseful Improvements in Pressure-Gages; and Ido declare the following tobea full,clear, and exact description of the invention, such as willenable others skilled in the art to which to it appertains to make anduse the same, reference being had to' the accompanying drawings, and tothe letters and figures of reference marked thereon, which form a partof this specification. Figure 1 is a front view of a pressure-gagehaving my improvement applied to it, the dial being removed from thecase and the lower prong of the forked link being shown as provided witha slot to receive the pin or screw in the end of the shorter branch ofthe Bourdon tube. Fig. 2 is a view of the forked link, showing the slotas formed in the upper prong thereof to receive the pin or screw in theend of the longer branch of the Bourdon tube. The nature of my inventionis defined in the claim hereinafter presented.

In the manufacture of pressure gages in which the Bourdon tube, formedin two branches, is used to give movement to the index, and the ends ofsaid branches are connected or pivoted to the ends of the fork of aforked link, considerable annoyance and difficulty often occurs infitting up the gage, on account of the variation in distance apart ofthe ends of the said branches of the Bourdon tube, to obviate which itnecessitates the bending of the prongs of the-fork more or less, tocause the holes in the ends of said prongs to coincide with those in theends of the branches, in order to receive screws or pivots toconnect thesaid prongs to the said branches. Moreover, when two Bourdon tubes arethus used there arises an inequality of movement, owing to difference inthe elasticity of them from variation in thickness of the metal or frombeing formed on curves of different radii, or from some inexplicablecause, and when their ends are connected to the prongs of the forkedlink, as heretofore, they are to some extent hampered-that is, the saidends of the branches do not have the freedom of movement, eachindependent of the other, that they do have when one of the prongs ofthe forked link is provided with my improvement, as hereinafterdescribed. 5

The object of my improvement is to overcome this difficulty, which Iaccomplish by providing the end of one prong of the fork with a slot, a,which may be open at one end of it, or it may be closed at both ends.direction of said slot may be vertical or it may be slightly inclined,the top of the slot when inclined being in a direction away from thetube branch to which the prong of the forked link provided with theslot-is connected.

In the drawings, A denotes the case of the gage; B and O, the branchesof the Bourdon tube which spring from the head D, secured to the caseand formed to communicate with a steam or exhaust pipe in the usualmanner.

E is the forked link, it having three arms,

a b c, as shown, the two shorter ones, a I), being connected to the endsof the branches B C by screws 11 e. The arm I) (see Fig. 2) is provided7 5 with a slot, a, open at one end of it and slightly inclined, asrepresented. The slot, instead of being open as shown, may be closed atboth its ends, and, if preferred, may be made in the arm a, instead ofb. (See Fig. 1.) The longer arm, 0, of the forked link is connected withthe toothed sectoral lever E by a connection-rod, G, pivoted to each, asshown.

The sectoral lever and the arbor H of the index are supported in aframe, I, secured to the case, and the teeth of the said sectoral leverconnect with the teeth of the pinion on the arbor H of the index in theusual way.

By providing one of the prongs of the forked link with the slot, asdescribed, the end of each 0 branch of the Bourdon tube will be free inits movements and consequently will be more sensitive to pressure andwill admit of nicer adjustment of the instrument, and the difficulty ofadjusting the prongs of the forked link 5 to properly connect them tothe branches is effectually obviated.

I am aware of United States Patents Nos. 145,726 and 272,860, thisinvention being an improvement upon the device shown in the I00 The 60latter patent. In No. 272,860 is shown a rigid forked link. As thusconstructed, its connection is made with great difficulty, and usuallyit is necessary to bend the fork. \Vith my in vention the fastening canbe readily and easily made. In No. 145,726 is shown a jointed forkedlink, which I desire not to use, as the rigid one is preferable. lhemeans of adjustably connecting the jointed link cannot be used for therigid link, as these means require that the arms of the fork should bemovable.

Having described my improvement, what I claim is In a pressure or vacuumgage of the kind shown and described, the rigid forked link having inone of the prongs of its fork a slot CHARLES B. 3OS\VORTII.

Witnesses:

S. N. Pirnn, WM. If. ilnlcs'rtm.

